Annotation of embedaddon/sqlite3/src/mem3.c, revision 1.1
1.1 ! misho 1: /*
! 2: ** 2007 October 14
! 3: **
! 4: ** The author disclaims copyright to this source code. In place of
! 5: ** a legal notice, here is a blessing:
! 6: **
! 7: ** May you do good and not evil.
! 8: ** May you find forgiveness for yourself and forgive others.
! 9: ** May you share freely, never taking more than you give.
! 10: **
! 11: *************************************************************************
! 12: ** This file contains the C functions that implement a memory
! 13: ** allocation subsystem for use by SQLite.
! 14: **
! 15: ** This version of the memory allocation subsystem omits all
! 16: ** use of malloc(). The SQLite user supplies a block of memory
! 17: ** before calling sqlite3_initialize() from which allocations
! 18: ** are made and returned by the xMalloc() and xRealloc()
! 19: ** implementations. Once sqlite3_initialize() has been called,
! 20: ** the amount of memory available to SQLite is fixed and cannot
! 21: ** be changed.
! 22: **
! 23: ** This version of the memory allocation subsystem is included
! 24: ** in the build only if SQLITE_ENABLE_MEMSYS3 is defined.
! 25: */
! 26: #include "sqliteInt.h"
! 27:
! 28: /*
! 29: ** This version of the memory allocator is only built into the library
! 30: ** SQLITE_ENABLE_MEMSYS3 is defined. Defining this symbol does not
! 31: ** mean that the library will use a memory-pool by default, just that
! 32: ** it is available. The mempool allocator is activated by calling
! 33: ** sqlite3_config().
! 34: */
! 35: #ifdef SQLITE_ENABLE_MEMSYS3
! 36:
! 37: /*
! 38: ** Maximum size (in Mem3Blocks) of a "small" chunk.
! 39: */
! 40: #define MX_SMALL 10
! 41:
! 42:
! 43: /*
! 44: ** Number of freelist hash slots
! 45: */
! 46: #define N_HASH 61
! 47:
! 48: /*
! 49: ** A memory allocation (also called a "chunk") consists of two or
! 50: ** more blocks where each block is 8 bytes. The first 8 bytes are
! 51: ** a header that is not returned to the user.
! 52: **
! 53: ** A chunk is two or more blocks that is either checked out or
! 54: ** free. The first block has format u.hdr. u.hdr.size4x is 4 times the
! 55: ** size of the allocation in blocks if the allocation is free.
! 56: ** The u.hdr.size4x&1 bit is true if the chunk is checked out and
! 57: ** false if the chunk is on the freelist. The u.hdr.size4x&2 bit
! 58: ** is true if the previous chunk is checked out and false if the
! 59: ** previous chunk is free. The u.hdr.prevSize field is the size of
! 60: ** the previous chunk in blocks if the previous chunk is on the
! 61: ** freelist. If the previous chunk is checked out, then
! 62: ** u.hdr.prevSize can be part of the data for that chunk and should
! 63: ** not be read or written.
! 64: **
! 65: ** We often identify a chunk by its index in mem3.aPool[]. When
! 66: ** this is done, the chunk index refers to the second block of
! 67: ** the chunk. In this way, the first chunk has an index of 1.
! 68: ** A chunk index of 0 means "no such chunk" and is the equivalent
! 69: ** of a NULL pointer.
! 70: **
! 71: ** The second block of free chunks is of the form u.list. The
! 72: ** two fields form a double-linked list of chunks of related sizes.
! 73: ** Pointers to the head of the list are stored in mem3.aiSmall[]
! 74: ** for smaller chunks and mem3.aiHash[] for larger chunks.
! 75: **
! 76: ** The second block of a chunk is user data if the chunk is checked
! 77: ** out. If a chunk is checked out, the user data may extend into
! 78: ** the u.hdr.prevSize value of the following chunk.
! 79: */
! 80: typedef struct Mem3Block Mem3Block;
! 81: struct Mem3Block {
! 82: union {
! 83: struct {
! 84: u32 prevSize; /* Size of previous chunk in Mem3Block elements */
! 85: u32 size4x; /* 4x the size of current chunk in Mem3Block elements */
! 86: } hdr;
! 87: struct {
! 88: u32 next; /* Index in mem3.aPool[] of next free chunk */
! 89: u32 prev; /* Index in mem3.aPool[] of previous free chunk */
! 90: } list;
! 91: } u;
! 92: };
! 93:
! 94: /*
! 95: ** All of the static variables used by this module are collected
! 96: ** into a single structure named "mem3". This is to keep the
! 97: ** static variables organized and to reduce namespace pollution
! 98: ** when this module is combined with other in the amalgamation.
! 99: */
! 100: static SQLITE_WSD struct Mem3Global {
! 101: /*
! 102: ** Memory available for allocation. nPool is the size of the array
! 103: ** (in Mem3Blocks) pointed to by aPool less 2.
! 104: */
! 105: u32 nPool;
! 106: Mem3Block *aPool;
! 107:
! 108: /*
! 109: ** True if we are evaluating an out-of-memory callback.
! 110: */
! 111: int alarmBusy;
! 112:
! 113: /*
! 114: ** Mutex to control access to the memory allocation subsystem.
! 115: */
! 116: sqlite3_mutex *mutex;
! 117:
! 118: /*
! 119: ** The minimum amount of free space that we have seen.
! 120: */
! 121: u32 mnMaster;
! 122:
! 123: /*
! 124: ** iMaster is the index of the master chunk. Most new allocations
! 125: ** occur off of this chunk. szMaster is the size (in Mem3Blocks)
! 126: ** of the current master. iMaster is 0 if there is not master chunk.
! 127: ** The master chunk is not in either the aiHash[] or aiSmall[].
! 128: */
! 129: u32 iMaster;
! 130: u32 szMaster;
! 131:
! 132: /*
! 133: ** Array of lists of free blocks according to the block size
! 134: ** for smaller chunks, or a hash on the block size for larger
! 135: ** chunks.
! 136: */
! 137: u32 aiSmall[MX_SMALL-1]; /* For sizes 2 through MX_SMALL, inclusive */
! 138: u32 aiHash[N_HASH]; /* For sizes MX_SMALL+1 and larger */
! 139: } mem3 = { 97535575 };
! 140:
! 141: #define mem3 GLOBAL(struct Mem3Global, mem3)
! 142:
! 143: /*
! 144: ** Unlink the chunk at mem3.aPool[i] from list it is currently
! 145: ** on. *pRoot is the list that i is a member of.
! 146: */
! 147: static void memsys3UnlinkFromList(u32 i, u32 *pRoot){
! 148: u32 next = mem3.aPool[i].u.list.next;
! 149: u32 prev = mem3.aPool[i].u.list.prev;
! 150: assert( sqlite3_mutex_held(mem3.mutex) );
! 151: if( prev==0 ){
! 152: *pRoot = next;
! 153: }else{
! 154: mem3.aPool[prev].u.list.next = next;
! 155: }
! 156: if( next ){
! 157: mem3.aPool[next].u.list.prev = prev;
! 158: }
! 159: mem3.aPool[i].u.list.next = 0;
! 160: mem3.aPool[i].u.list.prev = 0;
! 161: }
! 162:
! 163: /*
! 164: ** Unlink the chunk at index i from
! 165: ** whatever list is currently a member of.
! 166: */
! 167: static void memsys3Unlink(u32 i){
! 168: u32 size, hash;
! 169: assert( sqlite3_mutex_held(mem3.mutex) );
! 170: assert( (mem3.aPool[i-1].u.hdr.size4x & 1)==0 );
! 171: assert( i>=1 );
! 172: size = mem3.aPool[i-1].u.hdr.size4x/4;
! 173: assert( size==mem3.aPool[i+size-1].u.hdr.prevSize );
! 174: assert( size>=2 );
! 175: if( size <= MX_SMALL ){
! 176: memsys3UnlinkFromList(i, &mem3.aiSmall[size-2]);
! 177: }else{
! 178: hash = size % N_HASH;
! 179: memsys3UnlinkFromList(i, &mem3.aiHash[hash]);
! 180: }
! 181: }
! 182:
! 183: /*
! 184: ** Link the chunk at mem3.aPool[i] so that is on the list rooted
! 185: ** at *pRoot.
! 186: */
! 187: static void memsys3LinkIntoList(u32 i, u32 *pRoot){
! 188: assert( sqlite3_mutex_held(mem3.mutex) );
! 189: mem3.aPool[i].u.list.next = *pRoot;
! 190: mem3.aPool[i].u.list.prev = 0;
! 191: if( *pRoot ){
! 192: mem3.aPool[*pRoot].u.list.prev = i;
! 193: }
! 194: *pRoot = i;
! 195: }
! 196:
! 197: /*
! 198: ** Link the chunk at index i into either the appropriate
! 199: ** small chunk list, or into the large chunk hash table.
! 200: */
! 201: static void memsys3Link(u32 i){
! 202: u32 size, hash;
! 203: assert( sqlite3_mutex_held(mem3.mutex) );
! 204: assert( i>=1 );
! 205: assert( (mem3.aPool[i-1].u.hdr.size4x & 1)==0 );
! 206: size = mem3.aPool[i-1].u.hdr.size4x/4;
! 207: assert( size==mem3.aPool[i+size-1].u.hdr.prevSize );
! 208: assert( size>=2 );
! 209: if( size <= MX_SMALL ){
! 210: memsys3LinkIntoList(i, &mem3.aiSmall[size-2]);
! 211: }else{
! 212: hash = size % N_HASH;
! 213: memsys3LinkIntoList(i, &mem3.aiHash[hash]);
! 214: }
! 215: }
! 216:
! 217: /*
! 218: ** If the STATIC_MEM mutex is not already held, obtain it now. The mutex
! 219: ** will already be held (obtained by code in malloc.c) if
! 220: ** sqlite3GlobalConfig.bMemStat is true.
! 221: */
! 222: static void memsys3Enter(void){
! 223: if( sqlite3GlobalConfig.bMemstat==0 && mem3.mutex==0 ){
! 224: mem3.mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MEM);
! 225: }
! 226: sqlite3_mutex_enter(mem3.mutex);
! 227: }
! 228: static void memsys3Leave(void){
! 229: sqlite3_mutex_leave(mem3.mutex);
! 230: }
! 231:
! 232: /*
! 233: ** Called when we are unable to satisfy an allocation of nBytes.
! 234: */
! 235: static void memsys3OutOfMemory(int nByte){
! 236: if( !mem3.alarmBusy ){
! 237: mem3.alarmBusy = 1;
! 238: assert( sqlite3_mutex_held(mem3.mutex) );
! 239: sqlite3_mutex_leave(mem3.mutex);
! 240: sqlite3_release_memory(nByte);
! 241: sqlite3_mutex_enter(mem3.mutex);
! 242: mem3.alarmBusy = 0;
! 243: }
! 244: }
! 245:
! 246:
! 247: /*
! 248: ** Chunk i is a free chunk that has been unlinked. Adjust its
! 249: ** size parameters for check-out and return a pointer to the
! 250: ** user portion of the chunk.
! 251: */
! 252: static void *memsys3Checkout(u32 i, u32 nBlock){
! 253: u32 x;
! 254: assert( sqlite3_mutex_held(mem3.mutex) );
! 255: assert( i>=1 );
! 256: assert( mem3.aPool[i-1].u.hdr.size4x/4==nBlock );
! 257: assert( mem3.aPool[i+nBlock-1].u.hdr.prevSize==nBlock );
! 258: x = mem3.aPool[i-1].u.hdr.size4x;
! 259: mem3.aPool[i-1].u.hdr.size4x = nBlock*4 | 1 | (x&2);
! 260: mem3.aPool[i+nBlock-1].u.hdr.prevSize = nBlock;
! 261: mem3.aPool[i+nBlock-1].u.hdr.size4x |= 2;
! 262: return &mem3.aPool[i];
! 263: }
! 264:
! 265: /*
! 266: ** Carve a piece off of the end of the mem3.iMaster free chunk.
! 267: ** Return a pointer to the new allocation. Or, if the master chunk
! 268: ** is not large enough, return 0.
! 269: */
! 270: static void *memsys3FromMaster(u32 nBlock){
! 271: assert( sqlite3_mutex_held(mem3.mutex) );
! 272: assert( mem3.szMaster>=nBlock );
! 273: if( nBlock>=mem3.szMaster-1 ){
! 274: /* Use the entire master */
! 275: void *p = memsys3Checkout(mem3.iMaster, mem3.szMaster);
! 276: mem3.iMaster = 0;
! 277: mem3.szMaster = 0;
! 278: mem3.mnMaster = 0;
! 279: return p;
! 280: }else{
! 281: /* Split the master block. Return the tail. */
! 282: u32 newi, x;
! 283: newi = mem3.iMaster + mem3.szMaster - nBlock;
! 284: assert( newi > mem3.iMaster+1 );
! 285: mem3.aPool[mem3.iMaster+mem3.szMaster-1].u.hdr.prevSize = nBlock;
! 286: mem3.aPool[mem3.iMaster+mem3.szMaster-1].u.hdr.size4x |= 2;
! 287: mem3.aPool[newi-1].u.hdr.size4x = nBlock*4 + 1;
! 288: mem3.szMaster -= nBlock;
! 289: mem3.aPool[newi-1].u.hdr.prevSize = mem3.szMaster;
! 290: x = mem3.aPool[mem3.iMaster-1].u.hdr.size4x & 2;
! 291: mem3.aPool[mem3.iMaster-1].u.hdr.size4x = mem3.szMaster*4 | x;
! 292: if( mem3.szMaster < mem3.mnMaster ){
! 293: mem3.mnMaster = mem3.szMaster;
! 294: }
! 295: return (void*)&mem3.aPool[newi];
! 296: }
! 297: }
! 298:
! 299: /*
! 300: ** *pRoot is the head of a list of free chunks of the same size
! 301: ** or same size hash. In other words, *pRoot is an entry in either
! 302: ** mem3.aiSmall[] or mem3.aiHash[].
! 303: **
! 304: ** This routine examines all entries on the given list and tries
! 305: ** to coalesce each entries with adjacent free chunks.
! 306: **
! 307: ** If it sees a chunk that is larger than mem3.iMaster, it replaces
! 308: ** the current mem3.iMaster with the new larger chunk. In order for
! 309: ** this mem3.iMaster replacement to work, the master chunk must be
! 310: ** linked into the hash tables. That is not the normal state of
! 311: ** affairs, of course. The calling routine must link the master
! 312: ** chunk before invoking this routine, then must unlink the (possibly
! 313: ** changed) master chunk once this routine has finished.
! 314: */
! 315: static void memsys3Merge(u32 *pRoot){
! 316: u32 iNext, prev, size, i, x;
! 317:
! 318: assert( sqlite3_mutex_held(mem3.mutex) );
! 319: for(i=*pRoot; i>0; i=iNext){
! 320: iNext = mem3.aPool[i].u.list.next;
! 321: size = mem3.aPool[i-1].u.hdr.size4x;
! 322: assert( (size&1)==0 );
! 323: if( (size&2)==0 ){
! 324: memsys3UnlinkFromList(i, pRoot);
! 325: assert( i > mem3.aPool[i-1].u.hdr.prevSize );
! 326: prev = i - mem3.aPool[i-1].u.hdr.prevSize;
! 327: if( prev==iNext ){
! 328: iNext = mem3.aPool[prev].u.list.next;
! 329: }
! 330: memsys3Unlink(prev);
! 331: size = i + size/4 - prev;
! 332: x = mem3.aPool[prev-1].u.hdr.size4x & 2;
! 333: mem3.aPool[prev-1].u.hdr.size4x = size*4 | x;
! 334: mem3.aPool[prev+size-1].u.hdr.prevSize = size;
! 335: memsys3Link(prev);
! 336: i = prev;
! 337: }else{
! 338: size /= 4;
! 339: }
! 340: if( size>mem3.szMaster ){
! 341: mem3.iMaster = i;
! 342: mem3.szMaster = size;
! 343: }
! 344: }
! 345: }
! 346:
! 347: /*
! 348: ** Return a block of memory of at least nBytes in size.
! 349: ** Return NULL if unable.
! 350: **
! 351: ** This function assumes that the necessary mutexes, if any, are
! 352: ** already held by the caller. Hence "Unsafe".
! 353: */
! 354: static void *memsys3MallocUnsafe(int nByte){
! 355: u32 i;
! 356: u32 nBlock;
! 357: u32 toFree;
! 358:
! 359: assert( sqlite3_mutex_held(mem3.mutex) );
! 360: assert( sizeof(Mem3Block)==8 );
! 361: if( nByte<=12 ){
! 362: nBlock = 2;
! 363: }else{
! 364: nBlock = (nByte + 11)/8;
! 365: }
! 366: assert( nBlock>=2 );
! 367:
! 368: /* STEP 1:
! 369: ** Look for an entry of the correct size in either the small
! 370: ** chunk table or in the large chunk hash table. This is
! 371: ** successful most of the time (about 9 times out of 10).
! 372: */
! 373: if( nBlock <= MX_SMALL ){
! 374: i = mem3.aiSmall[nBlock-2];
! 375: if( i>0 ){
! 376: memsys3UnlinkFromList(i, &mem3.aiSmall[nBlock-2]);
! 377: return memsys3Checkout(i, nBlock);
! 378: }
! 379: }else{
! 380: int hash = nBlock % N_HASH;
! 381: for(i=mem3.aiHash[hash]; i>0; i=mem3.aPool[i].u.list.next){
! 382: if( mem3.aPool[i-1].u.hdr.size4x/4==nBlock ){
! 383: memsys3UnlinkFromList(i, &mem3.aiHash[hash]);
! 384: return memsys3Checkout(i, nBlock);
! 385: }
! 386: }
! 387: }
! 388:
! 389: /* STEP 2:
! 390: ** Try to satisfy the allocation by carving a piece off of the end
! 391: ** of the master chunk. This step usually works if step 1 fails.
! 392: */
! 393: if( mem3.szMaster>=nBlock ){
! 394: return memsys3FromMaster(nBlock);
! 395: }
! 396:
! 397:
! 398: /* STEP 3:
! 399: ** Loop through the entire memory pool. Coalesce adjacent free
! 400: ** chunks. Recompute the master chunk as the largest free chunk.
! 401: ** Then try again to satisfy the allocation by carving a piece off
! 402: ** of the end of the master chunk. This step happens very
! 403: ** rarely (we hope!)
! 404: */
! 405: for(toFree=nBlock*16; toFree<(mem3.nPool*16); toFree *= 2){
! 406: memsys3OutOfMemory(toFree);
! 407: if( mem3.iMaster ){
! 408: memsys3Link(mem3.iMaster);
! 409: mem3.iMaster = 0;
! 410: mem3.szMaster = 0;
! 411: }
! 412: for(i=0; i<N_HASH; i++){
! 413: memsys3Merge(&mem3.aiHash[i]);
! 414: }
! 415: for(i=0; i<MX_SMALL-1; i++){
! 416: memsys3Merge(&mem3.aiSmall[i]);
! 417: }
! 418: if( mem3.szMaster ){
! 419: memsys3Unlink(mem3.iMaster);
! 420: if( mem3.szMaster>=nBlock ){
! 421: return memsys3FromMaster(nBlock);
! 422: }
! 423: }
! 424: }
! 425:
! 426: /* If none of the above worked, then we fail. */
! 427: return 0;
! 428: }
! 429:
! 430: /*
! 431: ** Free an outstanding memory allocation.
! 432: **
! 433: ** This function assumes that the necessary mutexes, if any, are
! 434: ** already held by the caller. Hence "Unsafe".
! 435: */
! 436: static void memsys3FreeUnsafe(void *pOld){
! 437: Mem3Block *p = (Mem3Block*)pOld;
! 438: int i;
! 439: u32 size, x;
! 440: assert( sqlite3_mutex_held(mem3.mutex) );
! 441: assert( p>mem3.aPool && p<&mem3.aPool[mem3.nPool] );
! 442: i = p - mem3.aPool;
! 443: assert( (mem3.aPool[i-1].u.hdr.size4x&1)==1 );
! 444: size = mem3.aPool[i-1].u.hdr.size4x/4;
! 445: assert( i+size<=mem3.nPool+1 );
! 446: mem3.aPool[i-1].u.hdr.size4x &= ~1;
! 447: mem3.aPool[i+size-1].u.hdr.prevSize = size;
! 448: mem3.aPool[i+size-1].u.hdr.size4x &= ~2;
! 449: memsys3Link(i);
! 450:
! 451: /* Try to expand the master using the newly freed chunk */
! 452: if( mem3.iMaster ){
! 453: while( (mem3.aPool[mem3.iMaster-1].u.hdr.size4x&2)==0 ){
! 454: size = mem3.aPool[mem3.iMaster-1].u.hdr.prevSize;
! 455: mem3.iMaster -= size;
! 456: mem3.szMaster += size;
! 457: memsys3Unlink(mem3.iMaster);
! 458: x = mem3.aPool[mem3.iMaster-1].u.hdr.size4x & 2;
! 459: mem3.aPool[mem3.iMaster-1].u.hdr.size4x = mem3.szMaster*4 | x;
! 460: mem3.aPool[mem3.iMaster+mem3.szMaster-1].u.hdr.prevSize = mem3.szMaster;
! 461: }
! 462: x = mem3.aPool[mem3.iMaster-1].u.hdr.size4x & 2;
! 463: while( (mem3.aPool[mem3.iMaster+mem3.szMaster-1].u.hdr.size4x&1)==0 ){
! 464: memsys3Unlink(mem3.iMaster+mem3.szMaster);
! 465: mem3.szMaster += mem3.aPool[mem3.iMaster+mem3.szMaster-1].u.hdr.size4x/4;
! 466: mem3.aPool[mem3.iMaster-1].u.hdr.size4x = mem3.szMaster*4 | x;
! 467: mem3.aPool[mem3.iMaster+mem3.szMaster-1].u.hdr.prevSize = mem3.szMaster;
! 468: }
! 469: }
! 470: }
! 471:
! 472: /*
! 473: ** Return the size of an outstanding allocation, in bytes. The
! 474: ** size returned omits the 8-byte header overhead. This only
! 475: ** works for chunks that are currently checked out.
! 476: */
! 477: static int memsys3Size(void *p){
! 478: Mem3Block *pBlock;
! 479: if( p==0 ) return 0;
! 480: pBlock = (Mem3Block*)p;
! 481: assert( (pBlock[-1].u.hdr.size4x&1)!=0 );
! 482: return (pBlock[-1].u.hdr.size4x&~3)*2 - 4;
! 483: }
! 484:
! 485: /*
! 486: ** Round up a request size to the next valid allocation size.
! 487: */
! 488: static int memsys3Roundup(int n){
! 489: if( n<=12 ){
! 490: return 12;
! 491: }else{
! 492: return ((n+11)&~7) - 4;
! 493: }
! 494: }
! 495:
! 496: /*
! 497: ** Allocate nBytes of memory.
! 498: */
! 499: static void *memsys3Malloc(int nBytes){
! 500: sqlite3_int64 *p;
! 501: assert( nBytes>0 ); /* malloc.c filters out 0 byte requests */
! 502: memsys3Enter();
! 503: p = memsys3MallocUnsafe(nBytes);
! 504: memsys3Leave();
! 505: return (void*)p;
! 506: }
! 507:
! 508: /*
! 509: ** Free memory.
! 510: */
! 511: static void memsys3Free(void *pPrior){
! 512: assert( pPrior );
! 513: memsys3Enter();
! 514: memsys3FreeUnsafe(pPrior);
! 515: memsys3Leave();
! 516: }
! 517:
! 518: /*
! 519: ** Change the size of an existing memory allocation
! 520: */
! 521: static void *memsys3Realloc(void *pPrior, int nBytes){
! 522: int nOld;
! 523: void *p;
! 524: if( pPrior==0 ){
! 525: return sqlite3_malloc(nBytes);
! 526: }
! 527: if( nBytes<=0 ){
! 528: sqlite3_free(pPrior);
! 529: return 0;
! 530: }
! 531: nOld = memsys3Size(pPrior);
! 532: if( nBytes<=nOld && nBytes>=nOld-128 ){
! 533: return pPrior;
! 534: }
! 535: memsys3Enter();
! 536: p = memsys3MallocUnsafe(nBytes);
! 537: if( p ){
! 538: if( nOld<nBytes ){
! 539: memcpy(p, pPrior, nOld);
! 540: }else{
! 541: memcpy(p, pPrior, nBytes);
! 542: }
! 543: memsys3FreeUnsafe(pPrior);
! 544: }
! 545: memsys3Leave();
! 546: return p;
! 547: }
! 548:
! 549: /*
! 550: ** Initialize this module.
! 551: */
! 552: static int memsys3Init(void *NotUsed){
! 553: UNUSED_PARAMETER(NotUsed);
! 554: if( !sqlite3GlobalConfig.pHeap ){
! 555: return SQLITE_ERROR;
! 556: }
! 557:
! 558: /* Store a pointer to the memory block in global structure mem3. */
! 559: assert( sizeof(Mem3Block)==8 );
! 560: mem3.aPool = (Mem3Block *)sqlite3GlobalConfig.pHeap;
! 561: mem3.nPool = (sqlite3GlobalConfig.nHeap / sizeof(Mem3Block)) - 2;
! 562:
! 563: /* Initialize the master block. */
! 564: mem3.szMaster = mem3.nPool;
! 565: mem3.mnMaster = mem3.szMaster;
! 566: mem3.iMaster = 1;
! 567: mem3.aPool[0].u.hdr.size4x = (mem3.szMaster<<2) + 2;
! 568: mem3.aPool[mem3.nPool].u.hdr.prevSize = mem3.nPool;
! 569: mem3.aPool[mem3.nPool].u.hdr.size4x = 1;
! 570:
! 571: return SQLITE_OK;
! 572: }
! 573:
! 574: /*
! 575: ** Deinitialize this module.
! 576: */
! 577: static void memsys3Shutdown(void *NotUsed){
! 578: UNUSED_PARAMETER(NotUsed);
! 579: mem3.mutex = 0;
! 580: return;
! 581: }
! 582:
! 583:
! 584:
! 585: /*
! 586: ** Open the file indicated and write a log of all unfreed memory
! 587: ** allocations into that log.
! 588: */
! 589: void sqlite3Memsys3Dump(const char *zFilename){
! 590: #ifdef SQLITE_DEBUG
! 591: FILE *out;
! 592: u32 i, j;
! 593: u32 size;
! 594: if( zFilename==0 || zFilename[0]==0 ){
! 595: out = stdout;
! 596: }else{
! 597: out = fopen(zFilename, "w");
! 598: if( out==0 ){
! 599: fprintf(stderr, "** Unable to output memory debug output log: %s **\n",
! 600: zFilename);
! 601: return;
! 602: }
! 603: }
! 604: memsys3Enter();
! 605: fprintf(out, "CHUNKS:\n");
! 606: for(i=1; i<=mem3.nPool; i+=size/4){
! 607: size = mem3.aPool[i-1].u.hdr.size4x;
! 608: if( size/4<=1 ){
! 609: fprintf(out, "%p size error\n", &mem3.aPool[i]);
! 610: assert( 0 );
! 611: break;
! 612: }
! 613: if( (size&1)==0 && mem3.aPool[i+size/4-1].u.hdr.prevSize!=size/4 ){
! 614: fprintf(out, "%p tail size does not match\n", &mem3.aPool[i]);
! 615: assert( 0 );
! 616: break;
! 617: }
! 618: if( ((mem3.aPool[i+size/4-1].u.hdr.size4x&2)>>1)!=(size&1) ){
! 619: fprintf(out, "%p tail checkout bit is incorrect\n", &mem3.aPool[i]);
! 620: assert( 0 );
! 621: break;
! 622: }
! 623: if( size&1 ){
! 624: fprintf(out, "%p %6d bytes checked out\n", &mem3.aPool[i], (size/4)*8-8);
! 625: }else{
! 626: fprintf(out, "%p %6d bytes free%s\n", &mem3.aPool[i], (size/4)*8-8,
! 627: i==mem3.iMaster ? " **master**" : "");
! 628: }
! 629: }
! 630: for(i=0; i<MX_SMALL-1; i++){
! 631: if( mem3.aiSmall[i]==0 ) continue;
! 632: fprintf(out, "small(%2d):", i);
! 633: for(j = mem3.aiSmall[i]; j>0; j=mem3.aPool[j].u.list.next){
! 634: fprintf(out, " %p(%d)", &mem3.aPool[j],
! 635: (mem3.aPool[j-1].u.hdr.size4x/4)*8-8);
! 636: }
! 637: fprintf(out, "\n");
! 638: }
! 639: for(i=0; i<N_HASH; i++){
! 640: if( mem3.aiHash[i]==0 ) continue;
! 641: fprintf(out, "hash(%2d):", i);
! 642: for(j = mem3.aiHash[i]; j>0; j=mem3.aPool[j].u.list.next){
! 643: fprintf(out, " %p(%d)", &mem3.aPool[j],
! 644: (mem3.aPool[j-1].u.hdr.size4x/4)*8-8);
! 645: }
! 646: fprintf(out, "\n");
! 647: }
! 648: fprintf(out, "master=%d\n", mem3.iMaster);
! 649: fprintf(out, "nowUsed=%d\n", mem3.nPool*8 - mem3.szMaster*8);
! 650: fprintf(out, "mxUsed=%d\n", mem3.nPool*8 - mem3.mnMaster*8);
! 651: sqlite3_mutex_leave(mem3.mutex);
! 652: if( out==stdout ){
! 653: fflush(stdout);
! 654: }else{
! 655: fclose(out);
! 656: }
! 657: #else
! 658: UNUSED_PARAMETER(zFilename);
! 659: #endif
! 660: }
! 661:
! 662: /*
! 663: ** This routine is the only routine in this file with external
! 664: ** linkage.
! 665: **
! 666: ** Populate the low-level memory allocation function pointers in
! 667: ** sqlite3GlobalConfig.m with pointers to the routines in this file. The
! 668: ** arguments specify the block of memory to manage.
! 669: **
! 670: ** This routine is only called by sqlite3_config(), and therefore
! 671: ** is not required to be threadsafe (it is not).
! 672: */
! 673: const sqlite3_mem_methods *sqlite3MemGetMemsys3(void){
! 674: static const sqlite3_mem_methods mempoolMethods = {
! 675: memsys3Malloc,
! 676: memsys3Free,
! 677: memsys3Realloc,
! 678: memsys3Size,
! 679: memsys3Roundup,
! 680: memsys3Init,
! 681: memsys3Shutdown,
! 682: 0
! 683: };
! 684: return &mempoolMethods;
! 685: }
! 686:
! 687: #endif /* SQLITE_ENABLE_MEMSYS3 */
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